Device for breaking the connections of electric circuits



Aug. 21, 1928.

R. RUDENBERG ET AL DEVICE FOR BREAKING THE CONNECTIONS OF ELECTRIC CIRCUITS Filed July 2, 1926 M (MW,-

L1 KMR, M

i' Patented Aug. 21, 1928.

UNITED STATES PA ENT OFFICE.

BEIN HOLD RO'DENIBERQ OF BERLIN-GRUNEWALD, RI'J'DOIJ G. BERTHOLD, 1313312114- SIEMENSSTADT, AND KARL DONAT, OF BERLIN-CHARLOTTENBURG, GERMANY, AS

SIGNORS T0 SIEMENS-SCHUGKERTWERKE GESELLS CHAFT MIT nnscnnannrnn HAFTUNG, 0F SIEMENSSTA'DT, NEAR BERLIN, GERMANY, A CORPORATION 01 GERMANY.

' nnvrcn non nnmigme 'rnn connncrrons on nnnc'rnrc omcu'rrs.

Application flied July 2, 1926, Serial No. 120,194, and in Germany June 80, 1925.

Our invention relates to a device for breaking the connections of an electric circuit.

To avoid sparking in air-break switches and oil circuit breakers the breaking of d1- rect and alternating currents may take place in gas discharge tubes by connecting one or a plurality of such tubes in parallel rela tion with the main switch. Preferably mer- 10 cury vapor discharge tubes are used for this purpose because these permit the easy passage of heavy currents. When breaking alternating current the mercury vapor tube is frequently provided with two mercury elec trodes to enable an easy striking of the arc in the tube in both directions. It is necessar to strike the are or to ignite the switc ing tube at the very moment when the main switch is opened. The current to be broken is then directly transferred to the switching tube when the contacts of the switch are separated. Direct current may now be extinguished in known manner. In the case of alternating current for which our system is particularly applicable, the current extinguishes itself when next passing through zero. The switch tube has thus never to deal with more than half an alternating current period. The ignitlon of the gas discharge tube generally takes place by means of the known ignition electrodes." These surround, for instance, the gas discharge tube in the vicinity of the level of the mercury in the form of an ignition belt, band, ring or the like. The ignition electrodes may surround the tube at the outside or they may be located in the interior.

The object of our invention is an arrangement, for operating such gas discharge tubes in a particularly reliable manner and at the moment when the main switch is opened.

According to our invention the ignition electrodes are operated by an oscillation circuit which is fed by the are which is developed when the switch is opened. An inductance and a capacity in series connection may, for instance, be connected with the two poles of the main switch. It is well known that a circuit, containing such an inductance and capacity can beexcited by an are to oscillate atits natural period. .This oscillation circuit feeds the lgnition electrodes of the gas discharge tube by means of inductive, capacitive or conductive coupling. The arc of the main switch thus causes, while forming, the development of considerable voltages at the ignition electrodes of the gas discharge tube, ignites it and thus instantly transfers the current from itself to the discharge tube so that the eflect of the incipient are upon the contacts of the main switch is only slight. Y Preferably the natural frequency of the oscillation circuit should be made comparatively high. Particularly when breaking alternating current circuits the natural frequency of this oscillation circuit should be substantially higher than the customary alternating current frequency of about 50 cycles. This is advisable for the reason that the ignition electrodes should for initiating the ignition process have such a polarity that the main electrodes become negative under the action of the ignition electrode voltage. If now the natural frequency of the oscillation circuit is chosen correspondingly high, no regard need be taken to correct the polarity of the ignition electrode, as either the first half-wave of the natural oscillations having an igniting effect and since the second halfwave also follows very quickly after the commencement of the breaking operation at the mainswitch so that the current flows through the main switch for a minimum time only when it is taken over by the tube. Under certainconditions it is even advisable to provide a high-frequency oscillation circuit.

In the drawing afiixed hereto are illustrated several embodiments of our invention, of which Fig. 1, is a diagram of an embodiment in which each end of the secondary coil of the inductance is connected with one of the ignition electrodes,

Fig. 2, is a further embodiment in which one end of the secondary coil of the inductance is connected with both ignition electrodes and the other end through two stopping condensers with both main electrodes, Fig. 3, is a further embodiment in which or second I two secondary coils are each connected with one end with an ignition electrode and with the other end to one main electrode and Fig. 4, is a still further embodiment in which two unsymmetrical single-pole electron tubes are employed.

Identical parts are indicated by like numerals of reference in all the figures of the drawing.

Referring to Fig. 1, 1 is the electric line and 2 the line main switch. In parallel re lation to the main switch is connected a mercury vapor discharge tube 3 with twomercury electrodes 4 and 5. The current in the tube is switched in by means of two ignition bands or belts 6 and 7. To operate these ignition bands an oscillation circuit with the inductance 8 and the capacity 9 is provided in parallel relation to the main switch. lVhen the main switch is opened the arc generated will thus excite the said oscillation circuit. The reactance voltage of the oscillation circuit thereby produced is applied to the ignition electrodes through a secondary coil 10 and the current of the main switch is transferred to the mercury vapor tube.

The embodiment illustrated in Figure 2 of the drawing differs from that in Figure 1 by the secondary coil 10 of the inductance 8 being connected at one end to both ignition electrodes 6 and 7 while the other end is connected with the two main electrodes through two stopping condensers 11 and 12. The ignition currents supplied by the coil 10 may therefore flow independent of each other through the stopping condensers and through the main electrodes. The subsequent transfer process of the main current is otherwise the same as in the system according to Fig. 1.

In the embodiment according to Fig. 3 of the drawing the inductance 8 is coupled with two separate secondary coils 13 and 14. Each secondary coil is connected at one end with an ignition electrode and at the other end with the respective main electrode. This arrangement has the advantage that the polarity of the ignition belts may be chosen as desired.

Instead of employin a symmetric doublepole switch tube 3, as illustrated in the Figures 1 to 3 two unsymmetric single-pole electron tubes may be employed in which one mercury pole only is ignited. The two mercury vapor tubes 15 and 16 are connected in parallel relation to the main switch 2 with opposite polarities with respect to each other, but for the ignition an oscillation circuit is provided for each tube having the inductances' 8 and the capacities 9 which again operate the ignition belts 6 and 7 by means of inductive coupling.

As shown for instance in the embodiment illustrated in Fig. 2 of the drawing one or a plurality of capacities 11 and 12 may be memes suitably proportioned capacity the oscilla' tion resistance of the oscillating system is reduced so that the starting of the oscillations takes place with greater certainty.

It will be obvious to those skilled in the art that modifications may be made without departing from thespirit of our invention and from the scope of our claims.

What we claim is 1. In a device for breaking an electric circuit by means of a gas discharge tube having at least one ignition electrode and being con-v nected in parallel relation to the main switch, an oscillation circuit connected to the two sides of said switch and adapted to be excited by the opening arc of said switch and to operate the ignition electrode-of said gas discharge tube.

2. In a device for breaking an electric circuit by means of a gas discharge tube having ignition electrodes and being connected in parallel relation to the main switch, an oscillation circuit having its inductance and capacity connected in parallel I relation to the two poles of said switch and being excited by the opening are of said switch and being adapted to operate the ignition electrodes of said discharge tube.

3. In a device for breaking an electric circuit by means of a gas having ignition electrodes and being connected in parallel relation to the main switch, an frequency which is considerably higher than the normal alternating current frequency of the line controlled by the switch, said circuit being connected in parallel to the two sides of said switch to be excited by the opening nections to operate the ignition electrodes of said discharge tube by the oscillatory current produced in. said oscillative circuit.

4. In a device for breaking an electric circuit by means of a gas discharge tube having ignition electrodes and being connected in parallel relation to the main switch, an oscillation circuit of a natural high-frequency connected to the two sides of said switch to be excited by the opening are of said switch, and circuit connections to operdischarge tube oscillation circuit of a natural are of said switch, and circuit conate the ignition electrodes of said discharge nected in parallel relation to the two poles of said switch, said oscillatory circuit being excited by the opening arc of said switch and having suitable clrcuit connections to operate the ignition electrodes of said discharge tube.

6. In a device for breaking an electric circuit by means of a gas discharge tube having ignition electrodes and being connected in parallel relation to the main switch, an oscillation circuit of a natural high-frequency having its inductance and capacity connected in parallel relation to the two poles of said switch so that said circuit is excited by the opening arc of said switch, said circuit having suitable connections coupled to it for operating the ignition electrodes of said discharge tube.

7 In a device for breaking an electric circuit by means of a gas discharge tube having ignition electrodes and being connected in parallel relataion to the main switch, an oscillation circuit connected to the two sides of said switch and adapted to be excited by the opening arc of sai switch and to operate the ignition electrodes of said gas discharge tube, and a capacity connected in parallel relation to said switch.

8. In a device for breaking an electric circuit by means of a gas discharge tube having ignition electrodes and being connected in parallel relation to the main switch, an oscillation circuit having its inductance and capacity connected in parallel relation to the two poles of said switch, and being excited by the opening are of said switch, and

being adapted to operate the ignition ele c.-

trodes of said discharge tube, and a capacity connected in parallel relation to said switch,

In testimony whereof we afiix our signatures.

REINHOLD RUDENBERG. RUDOLF G. BERTHOLD. KARL DONAT. 

